2009 NISSAN LATIO engine coolant

EC-1192< SERVICE INFOMATION >
[MR TYPE 2]
DTC P0117, P0118 ECT SENSOR
DTC P0117, P0118 ECT SENSOR
Component Description INFOID:0000000004501092
The engine coolant temperature sensor is used to detect the engine
coolant temperature. The sensor modifies a voltage signal from the
ECM. The modified signal returns to the ECM as the engine coolant
temperature input. The sensor uses a thermistor which is sensitive to
the change in temperature. The elec trical resistance of the ther-
mistor decreases as temperature increases.

*: This data is reference value and is measured between ECM terminal 38 (Engine
coolant temperature sensor) and ground.
CAUTION:
Do not use ECM ground terminals when measuring in put/output voltage. Doing so may result in dam-
age to the ECM's transistor. Use a ground ot her than ECM terminals, such as the ground.
On Board Diagn osis Logic INFOID:0000000004500023
These self-diagnoses have the one trip detection logic.
FAIL-SAFE MODE
When the malfunction is detected, the ECM enters fail-safe mode and the MIL lights up. SEF594K
Engine coolant temperature
°C ( °F) Voltage* V Resistance k
Ω
–10 (14) 4.4 7.0 - 11.4 20 (68) 3.5 2.1 - 2.9
50 (122) 2.2 0.68 - 1.00
90 (194) 0.9 0.236 - 0.260 SEF012P
DTC No.
Trouble Diagnosis
Name DTC detecting condition Possible Cause
P0117
0117 Engine coolant tem-
perature sensor cir-
cuit low input An excessively low voltage from the sensor is
sent to ECM. • Harness or connectors
(Engine coolant temperature sensor circuit is
open or shorted.)
• Engine coolant temperature sensor
P0118
0118 Engine coolant tem-
perature sensor cir-
cuit high input An excessively high voltage from the sensor is
sent to ECM.

EC
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DTC Confirmation Procedure
INFOID:0000000004500024
NOTE:
If DTC Confirmation Procedure has been previously conduc ted, always turn ignition switch OFF and wait at
least 10 seconds before conducting the next test.
WITH CONSULT-III
1. Turn ignition switch ON and wait at least 5 seconds.
2. Check DTC.
3. If DTC is detected, go to EC-1194, " Diagnosis Procedure " .
Detected items Engine operating condition in fail-safe mode
Engine coolant temper- ature sensor circuit Engine coolant temperature will be determined by ECM based on the following condition.
CONSULT-III displays the engine coolant temperature decided by ECM.
Condition Engine coolant temperature decided
(CONSULT-III display)
Just as ignition switch is turned ON or START 40 °C (104 °F)
Approx. 4 minutes or more after engine starting. 80 °C (176 °F)
Except as shown above 40 - 80
°C (104 - 176 °F)
(Depends on the time)
When the fail-safe system for engine coolant temperature sensor is activated, the cooling fan operates while
engine is running.

DTC P0117, P0118 ECT SENSOR
EC-1195
< SERVICE INFOMATION >
[MR TYPE 2] C
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OK or NG OK >> GO TO 2.
NG >> Repair or replace ground connections. 2.
CHECK ECT SENSOR POWER SUPPLY CIRCUIT
1. Disconnect engine coolant temperature (ECT) sensor (1) har- ness connector.
- : Vehicle front
2. Turn ignition switch ON.
3. Check voltage between ECT sensor terminal 1 and ground with CONSULT-III or tester.
OK or NG OK >> GO TO 3.
NG >> Repair open circuit or short to ground or short to power
in harness or connectors. 3.
CHECK ECT SENSOR GROUND CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch OFF.
2. Disconnect ECM harness connector.
3. Check harness continuity between ECM terminal 44 and ECT sensor terminal 2. Refer to Wiring Diagram.
4. Also check harness for short to ground and short to power.
OK or NG OK >> GO TO 4.
NG >> Repair open circuit or short to ground or short to power in harness or connectors. 4.
CHECK ENGINE COOLANT TEMPERATURE SENSOR:
Vehicle front
1. Body ground E24 2. Engine ground F9 3. Engine ground F16
4. Body ground E15 BBIA0698E
PBIB3324E
Voltage: Approximately 5V
PBIB0080E
Continuity should exist.

EC-1196< SERVICE INFOMATION >
[MR TYPE 2]
DTC P0117, P0118 ECT SENSOR
Refer to EC-1190, " Component Inspection " .
OK or NG OK >> GO TO 5.
NG >> Replace engine coolant temperature sensor. 5.
CHECK INTERMITTENT INCIDENT
Refer to EC-1138 .
>> INSPECTION END
Component Inspection INFOID:0000000004501094
ENGINE COOLANT TEMPERATURE SENSOR
1. Check resistance between engine coolant temperature sensor terminals 1 and 2 as shown in the figure.

2. If NG, replace engine coolant temperature sensor.
Removal and Installation INFOID:0000000004501095
ENGINE COOLANT TEMPERATURE SENSOR
Refer to CO-47, " Component " . PBIB2005E
Temperature
°C ( °F) Resistance k Ω
20 (68) 2.1 - 2.9
50 (122) 0.68 - 1.00
90 (194) 0.236 - 0.260 SEF012P

EC-1202< SERVICE INFOMATION >
[MR TYPE 2]
DTC P0125 ECT SENSOR
DTC P0125 ECT SENSOR
Component Description INFOID:0000000004501093
The engine coolant temperature sensor is used to detect the engine
coolant temperature. The sensor modifies a voltage signal from the
ECM. The modified signal returns to the ECM as the engine coolant
temperature input. The sensor uses a thermistor which is sensitive to
the change in temperature. The elec trical resistance of the ther-
mistor decreases as temperature increases.

*: This data is reference value and is measured between ECM terminal 38 (Engine
coolant temperature sensor) and ground.
CAUTION:
Do not use ECM ground terminals when measuring in put/output voltage. Doing so may result in dam-
age to the ECM's transistor. Use a ground ot her than ECM terminals, such as the ground.
On Board Diagn osis Logic INFOID:0000000004500038
NOTE:
• If DTC P0125 is displayed with P0117 or P0118, firs t perform the trouble diagnosis for DTC P0117 or P0118.
Refer to EC-1193, " DTC Confirmation Procedure " .
• If DTC P0125 is displayed with P0116, first perform the trouble diagnosis for DTC P0116. Refer to EC-1202," DTC Confirmation Procedure " .
DTC Confirmation Procedure INFOID:0000000004500039
CAUTION:
Be careful not to overheat engine.
NOTE:
If DTC Confirmation Procedure has been previously conduc ted, always turn ignition switch OFF and wait at
least 10 seconds before conducting the next test.
WITH CONSULT-III
1. Turn ignition switch ON.
2. Select “DATA MONITOR” mode with CONSULT-III.
3. Check that “COOLAN TEMP/S” is above 10 °C (50 °F). SEF594K
Engine coolant temperature
°C ( °F) Voltage* V Resistance k
Ω
–10 (14) 4.4 7.0 - 11.4 20 (68) 3.5 2.1 - 2.9
50 (122) 2.2 0.68 - 1.00
90 (194) 0.9 0.236 - 0.260 SEF012P
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0125
0125 Insufficient engine cool-
ant temperature for
closed loop fuel control • Voltage sent to ECM from the sensor is not
practical, even when some time has passed
after starting the engine.
• Engine coolant temperature is insufficient for closed loop fuel control. • Harness or connectors
(High resistance in the circuit)
• Engine coolant temperature sensor
• Thermostat

DTC P0125 ECT SENSOR
EC-1203
< SERVICE INFOMATION >
[MR TYPE 2] C
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If it is above 10
°C (50 °F), the test result will be OK.
If it is below 10 °C (50 °F), go to following step.
4. Start engine and run it for 65 minutes at idle speed. If “COOLAN TEMP/S” increases to more than 10 °C (50 °F) within 65 minutes, stop engine because
the test result will be OK.
5. Check DTC.
6. If DTC is detected, go to EC-1203, " Diagnosis Procedure " .
WITH GST
Follow the procedure “WITH CONSULT-III” above.
Diagnosis Procedure INFOID:00000000045000401.
CHECK GROUND CONNECTIONS
1. Turn ignition switch OFF.
2. Loosen and retighten ground screw on the body.
Refer to EC-1144, " Ground Inspection " .
OK or NG OK >> GO TO 2.
NG >> Repair or replace ground connections. 2.
CHECK ENGINE COOLANT TEMPERATURE SENSOR
Refer to EC-1204, " Component Inspection " .
OK or NG OK >> GO TO 3.
NG >> Replace engine coolant temperature sensor. 3.
CHECK THERMOSTAT OPERATION
When the engine is cold [lower than 70 °C (158 °F)] condition, grasp lower radiator hose and confirm the engine
coolant does not flow.
OK or NG OK >> GO TO 4.
NG >> Repair or replace thermostat. Refer to CO-45, " Removal and Installation " .
4.
CHECK INTERMITTENT INCIDENT
Refer to EC-1138 .
Refer to EC-1194, " Wiring Diagram " .
>> INSPECTION END :
Vehicle front
1. Body ground E24 2. Engine ground F9 3. Engine ground F16
4. Body ground E15 BBIA0698E

EC-1204< SERVICE INFOMATION >
[MR TYPE 2]
DTC P0125 ECT SENSOR
Component Inspection INFOID:0000000004501098
ENGINE COOLANT TEMPERATURE SENSOR
1. Check resistance between engine coolant temperature sensor terminals 1 and 2 as shown in the figure.

2. If NG, replace engine coolant temperature sensor.
Removal and Installation INFOID:0000000004501099
ENGINE COOLANT TEMPERATURE SENSOR
Refer to CO-47, " Component " . PBIB2005E
Temperature
°C ( °F) Resistance k Ω
20 (68) 2.1 - 2.9
50 (122) 0.68 - 1.00
90 (194) 0.236 - 0.260 SEF012P

DTC P0127 IAT SENSOR
EC-1205
< SERVICE INFOMATION >
[MR TYPE 2] C
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DTC P0127 IAT SENSOR
Component Description INFOID:0000000004501162
The intake air temperature sensor is built-into mass air flow sensor
(1). The sensor detects intake air temperature and transmits a signal
to the ECM.
The temperature sensing unit uses a thermistor which is sensitive to
the change in temperature. Electric al resistance of the thermistor
decreases in response to the temperature rise.

*: This data is reference value and is measured between ECM terminal 46 (Intake air
temperature sensor) and ground.
CAUTION:
Do not use ECM ground terminals when measuring input/output
voltage. Doing so may result in damage to the ECM's transistor.
Use a ground other than ECM te rminals, such as the ground.
On Board Diagnosis Logic INFOID:0000000004500044
DTC Confirmation Procedure INFOID:0000000004500045
CAUTION:
Always drive vehicle at a safe speed.
NOTE:
If DTC Confirmation Procedure has been previously conduc ted, always turn ignition switch OFF and wait at
least 10 seconds before conducting the next test.
TESTING CONDITION:
This test may be conducted with the drive wheels lifted in the shop or by driving the vehicle. If a road
test is expected to be easier, it is unnecessary to lift the vehicle.
WITH CONSULT-III
1. Wait until engine coolant temperature is less than 96 °C (205 °F)
a. Turn ignition switch ON.
b. Select “DATA MONITOR” mode with CONSULT-III.
c. Check the engine coolant temperature.
d. If the engine coolant temperature is not less than 96 °C (205 °F), turn ignition switch OFF and cool down
engine.
• Perform the following steps before engine coolant temperature is above 96 °C (205 °F). PBIA9559J
Intake air temperature
°C ( °F) Voltage* V Resistance k
Ω
25 (77) 3.3 1.800 - 2.200
80 (176) 1.2 0.283 - 0.359 SEF012P
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0127
0127 Intake air temperature
too high Rationally incorrect voltage from the sensor is
sent to ECM, compared with the voltage signal
from engine coolant temperature sensor. • Harness or connectors
(Intake temperature sensor circuit is open
or shorted)
• Intake air temperature sensor